2o6 Bulletin 29 370 



according to Dall, the shells of this group of Miltha have the 

 major cardinal tooth deeply bifid, the posterior scar very small, 

 and the anterior very narrow. 



It is interesting that we should have found a representative 

 of both groups of Miltha, though evidently they are very rare in 

 the blue clays. 



Locality. — (Exp'd '16) Zone H, Rio Cana at Caimito. 



Phacoides (Parvilucina) yaquensis Gabb 

 Plate 35, Figure 8 

 Lucina Yaquensis Gabb, Trans. Amer. Phil. Soc, vol. 15, p. 251, 



1873- 

 Phacoides { Par vi lucina) yaquensisTiaW., Trans. Wagner Inst. Sci., vol. 

 3, pt. 6, p. 1382, 1903. 



A Parvihicina which accords with Gabb's description of his 

 unfigured yaquensis is exceedingly common at Cercado. Besides 

 the more apparent concentric lines, some shells show a very faint 

 radial sculpture. Dall gives 4 mm. as the length of his largest 

 specimen from Bowden where the species also is found. Our 

 largest is 3.50 long and 3 in altitude. 



Localities — (Exp'd '16) Bluff 3, Cercado de Mao (hundreds 

 of shell) ; Zone H, Rio Cana at Caimito (scarce). 



Phacoides (Bellucina) actinus Dall 



We collected four valves of a Bellucina either identical with 

 or very closely allied to P. actinus from Bowden. Like that 

 species our shells have about sixteen, radial, rounded riblets 

 crossed by ridged concentric lines, and the sculpture appears pre- 

 cisely like Dr. Dall's figure of actinus. Only our valves seem 

 slightly more excavated on the dorsal margin with the beaks 

 sharper and more curved. This is very probably due to the fact 

 that the umbones are all worn, the outer surface of the beaks 

 being entirely eroded. 



Locality. — (Exp'd '16) Zone H, Rio Cana at Caimito. 



